This document discusses functional orthodontic appliances. It defines functional appliances as loose, removable intra-oral devices that alter muscle forces against teeth and craniofacial structures. It then discusses several types of functional appliances including twin blocks, bionators, activators, and oral screens. For each appliance, it describes the history, design, mode of action, indications, and effectiveness. The document provides detailed information on how functional appliances work to influence soft tissues, muscles, teeth, and jaw skeletons to correct malocclusions.

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Dr. Mohammed Alruby
Functional appliances
Prepared by:
Dr Mohammed Alruby
‫رخيص‬ ‫من‬ ‫تتوقعه‬ ‫فال‬ ‫جدا‬ ‫غالي‬ ‫الوفاء‬
Functional orthodontic appliances

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Dr. Mohammed Alruby
Definition: loose, usually removable intra-oral device which alter the muscle force against the
teeth and cranio-facial skeleton.
They are dynamic appliance depend on altered neuro-muscular action to affect bony growth and
occlusal development and also in maxilla than mandible
They are usually used in mixed dentition (ADA 1992)
Growth modification: making limited change in size of the cranio-facial complex
Time treatment: depend on growth spurt that differ in boys and girls
= early treatment usually involves two phase of treatment:
1- Functional phase
2- Fixed phase
=early start treatment can effect on the improvement of malocclusion so decrease the
psychological impact
Types of occlusion treatment with functional appliances
- Class II div 1
- Class I div 2
- Class III
- Open bite
How functional appliance work
Functional appliance influence four principle regions
1- Oro-facial soft tissue:
Teeth sit between the tongue on one side and the lips and cheeks on the other side
Correction can occur by improve the soft tissue environment surrounding the dentition
Incorporating oral screens or shields constructed in wires or acrylic as part of appliance
2- Muscles of mastication:
Forward positioning the mandible results in stretch and alteration in the activity of muscles of
mastication, particularly involved in elevation and retraction of mandible
The force transmitted to the dentition via the appliance
electo-myographic studies shown hyperactivity of the lateral pterygoid on protrusion of the
mandible ( Mac-Namara 1973)
3- Dentition and occlusion:
Forward position of mandible also generate an inter-maxillary force directed between the
maxillary and mandibular dentition
= class II component force aid in reduction of overjet by tipping of teeth
= change in mandibular position also associate with change in the vertical dimension, that
facilitate eruption of buccal teeth
= this eruption can be controlled by capping of the teeth in buccal segment
4- Jaw skeleton;
The force affects the bone -------- remodeling
The force affects the condyle ------- growth changes
a- Additional over growth of the mandible
b- Accelerate growth of the mandible
c- Change the direction of growth
d- Restricted growth of maxilla
e- Change the position of condyle and glenoid fossa

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Dr. Mohammed Alruby
= studies of functional appliance like Herbest shown forward movement in the glenoid fossa
through bony remodeling. The overall treatment time is usually in the region of 9 to 12 months
depending on the size of initial overjet, the average overjet reduction is approximately 1mm / year
Classification:
1- Myotonic: depend on the muscle mass for their action, large mandibular opening 8 – 10
mm worked by passive muscle stretch as Harvold
2- Myodynamic: depend on muscle activity for their function, median mandibular opening >
5mm
Work by stimulating muscle activity; Andreson
Proffit et al 2012:
1- Passive tooth born: Andreson
2- Active tooth born: Twin block
3- Tissue born: Frankel
According to its mode of action:
1- Utilizing the forces of muscles of mastication
2- Utilizing the forces of circum-oral musculature
3- Reducing the forces of circum-oral musculature
According to treatment principle:
1- Force application: that lead to primary alteration in form with secondary adaptation in
function
2- Force elimination: the abnormal and environmental influences are eliminated, allowing
optimal development
According to its fitness:
1- Closely fitting
2- Loosely fitting
Types of appliances
1- Flat anterior bite plane
It is a functional appliance because it alters the muscle force
against the teeth and cranio-facial
skeleton ------- depend on altered neuro-muscular
action to affect bony growth and occlusal
development, but we did not include
it in the classification
2- Twin block: William Clark 1988
the most popular functional appliances in Uk and this because it will tolerate by patients, it
constructed into two parts (Blocks) as the name suggested, the blocks need to be at least 5mm in
height, which prevent patient from biting on blocks on top of other

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Dr. Mohammed Alruby
= lower block occludes in front of upper one
= block height: ----- 8mm ----- Mitchel 2013
7mm ------ Clark 1988
= the inclined planes of these blocks are approximately 70 degree to occlusal plane --- Clark 1988
(height more than 5mm)
History:
= William Clark 1977 ---- Scottish orthodontist
= since it was difficult to hold mandible forward at 90 degree bite block angle, the angulation
changed to 45 degree
= the angulation changed to 70 degree to allow more horizontal movement but if patient fail to put
mandible forward, degree changed to 45 degree
= can use extra-oral traction to produce 200 – 300 gm on each side for 8 – 10 hours / day to
produce orthodontic effect
Advantageous:
1- Increased patients comfort, can wear full time without problem
2- Ability to expand the upper arch using midline screw
3- Easy reactivation of appliance to a more postured position by adding to the acrylic on the
blocks
4- Appliance robust and relatively easy to fabricate
5- Headgear can easily attach to upper arch in case of maxillary protrusion
6- Can use expansion screw in anterior segment to correct retroclination in class II div 2
Side effect:
Residual posterior lateral open bite at the end of treatment of the functional phase
N: B:
Some clinician trimmed acrylic blocks from the occlusal surface of upper blocks to allow lower
molars to erupt any remaining lateral open bite are closed down in fixed appliance phase of
treatment
Design:
Upper:
Clasp at 1st
premolars / 1st
molars
Midline expansion screw – expanded upper arch
Blocks
Optional -– labial bow: no benefit
--- springs;/ screw to procline incisors
Lower:
Clasp for 1st
premolar / 1st
molars
Incisors capping
Blocks: 70 degree to occlusal plane, mesial to 1st
molars to allow grinding to accelerate eruption

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Dr. Mohammed Alruby
Occlusal registration:
- Horizontally: -- edge to edge relationship, maximum forward posture 2mm
- Vertically: -- separation of buccal teeth, height of blocks approximately 5mm depend on
bite depth
Block height:
Small: -- patient can bite on block
Large: --- intrude on freeway space, comfort and ability to seal the lips
= in bite registration, the mandible is sagittaly advanced by 5 to 7mm and vertically the bite is
opened by 3 – 5mm at premolar region
Reactivation:
Addition of acrylic
Advancement screws
Problems and solutions:
 Solutions to lower appliance problem:
= avoid clasps on deciduous molar but clasps on 4 premolars
= avoid multiple loose deciduous teeth --- wait for extraction
= short interval between impression and fit
= lower incisor capping and / or ball ended incisor clasp aid fixation and stability
 Solution to posterior open bite:
= occurs as over bite cannot be reduced at the speed of overjet correction
= exacerbated by extrusion of upper incisors that accompanies retroclinations
= trim upper block, encourage lower molar to erupt as overjet reduces (remove lower molar clasp)
= lower incisors capping
= night wear only at end of functional phase
= upper removable appliance URA with steep and deep bit planes as retainer
Effectiveness of twin block:
= early treatment: (O’Brien et al 2003a)
Reduction of overjet
Correction of molars relationship
Reduction of severity malocclusion
= psychological effect of early treatment: (O’ Brien et al 2003 b)
= failure rate: (O’Brien et al 2003c):
Twin block 34%
Failure rate lowered when started treatment early than adolescent age, in early treatment; there
is no improvement over 8 -9 years
3- Bionator
Balter 1950 in Germany (Wilhelm Balter)
= the equilibrium between the tongue and circum oral muscles responsible for the shape of the
arch and intercuspation
= tooth born, Myodynamic, class II treatment
= the acrylic block was considerably reduced and more elastic than activator (Eirew 1981)
= it is also not easily reactivated, it either require remake or the appliance must be sectioned,
advanced and then put together again in the laboratory
Useful in:
Cases with poor undercut on lower teeth
Multiple exfoliating deciduous teeth

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Dr. Mohammed Alruby
Loss of 1st
permanent molars
There are 3 types of Bionator:
- Standard
- Class III appliance
- Open bite type
Standard type:
= used for class II div 1 and class II with narrow dental arch
= slender acrylic body fitted in lingual aspects of mandibular arch and part of maxillary one
= acrylic extended up distal to 1st
permanent molars, the maxillary plates cover only the molars
and premolars with anterior region remain uncovered
= acrylic extended 2mm below gingival margin
= the inter-occlusal space of some buccal teeth is fitted with acrylic extended over half of occlusal
surface of teeth to stabilize the appliance
= palatal 1.2mm coffin spring was incorporating into the appliance and designed to sit away from
the palate, stimulating the tongue to adapt a more anterior position and helping to stabilize the
Bionator in the oral cavity
= buccal wire shield was also incorporated to hold the cheeks away from the buccal segment and
allow passive expansion of the dental arches
Class III appliance:
= used in case of mandibular prognathism, the acrylic parts are similar to the standard appliance
= the palatal arch is placed in opposite direction so that the rounded arch is placed anteriorly
= the vestibular wire runs over the lower incisors instead of terminating at the lower canines
Open bite appliance:
= used in open bite cases
=palatal arch and vestibular wire are same as standard
= the maxillary acrylic portion is modified so that even the anterior area is covered ---- prevent
tongue from thrusting between the teeth as tongue responsible for open bite
Bite registration:
As the same way as activator, if overjet is too much a step wise advancement is preferred
Indications:
1- Class II div 1 the:
Well aligned dental arch
Retruded mandible
Labial tipping of upper incisors
No very skeletal discrepancy
2- Class III: ----- class III Bionator
3- Open bite: ----- open bite Bionator
N: B: headgear or Bionator:
= Favorable growth observed in about 75% of those receiving early treatment with either headgear
or functional appliances
= The differences between treated and untreated controls disappeared when both groups received
comprehensive fixed appliance treatment during adolescent
= early treatment is also less effective because no reduction in average time in fixed appliance
during second stage of treatment, and it did not decrease the proportion of complex treatment
involving extraction or orthognathic surgery

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Dr. Mohammed Alruby
4- Activator
Activator from group of loosely fitting appliance that come in single piece or monoblock, they
posture the mandible forward by lingual extension of acrylic monoblock
History:
= Kingsley 1879 device Vulcanite palatal plate to be used in patient having retruded mandible
= this Vulcanite plate consists of an anterior inclined that guided the mandible to forward position
as that patient closed on it
= Hotz devised Vorbiss plate which is modification of Kingsly
= Pierre Robin devised appliance called monoblock which is single block Vulcanite, positioned
the mandible forward with glossoptosis and mandibular retrognathism, tongue thrust.
= Viaggo Andresen 1908 in Denmark, developed loose fitting appliance which he is 1st
used on his
daughter: he made a modified Hawley type retainer on maxillary arch and he added horse shoe
shaped acrylic on lingual area, which help to positioned the mandible
- He was made this appliance to his daughter who was going for 3 months’ vacation, after
these 3 months, he found a marked sagittal correction and improvement of facial profile
- Andresen called that is biomechanical working retainer
- Later Andresen moved over to Norway and team up with Karl Humple and do a lot of
changes in this device to develop the final one called Norwegian appliance
= Huple worked from 1939 – 1945 and laid down (shaking theory) that based upon the functional
adaptation hypothesis of William Rwax, this theory stated that (the muscular stimuli are adequate
influences, creating an adaptation changes in the periodontal tissue and alveolar bone)
Rule of eight 8:
The forward position and vertical opening must equal 8mm
H activator: more horizontal advancement
V activator: more vertical advancement
Indications:
1- Class II div 1 malocclusion
2- Class II div 2 malocclusion
3- Class III malocclusion
4- Class I deep bite
5- Post treatment retention
6- Primary treatment before fixed appliance to improve skeletal jaw relationship
Contraindication:
1- Class I with crowded teeth
2- Excessive lower facial height
3- Severely proclined lower incisors
4- Patients with nasal stenosis caused by structural problem
5- Patient non-growing individuals
Mode of action:
= according to Andresen and Karl Haupl, the activator induces muscular, skeletal adaptation by
introducing a new pattern of mandibular closure
= the appliance loosely fits into the mouth, the patient has to move the mandible forward to engage
the appliance, this results in stretching of the elevator muscles and muscles of mastication which
starts contracts. This will generate energy which cause:
1- Prevention of further forward growth of maxillary dento-alveolar process
2- Movement of maxillary dento-alveolar process distally
3- A reciprocal forward force on the mandible

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Dr. Mohammed Alruby
((viscoelastic property)): passive tension caused by stretching of muscles, soft tissue tendinous
tissue, this responsible for action of activator
Bite construction:
= inter-maxillary wax record to relate the mandible to maxilla in three dimension of space
= the bite registration involves repositioning the mandible in forward direction as well as opening
bite vertically
= mandible advanced 4–5 mm + bite opened 2-3mm beyond freeway space
N: B:
== single maximum advancement will generate class II forces, which when transmitted to the
dentition will result in dento-alveolar rather than skeletal change (Frankel 1989)
== in clinical practice it seems to be little difference in outcomes either skeletal or dento-alveolar
if mandible is maximally or incrementally postured forward (Banks etal 2004)
Vertically: there should be approximately 2mm of separation between the incisors, the exception
of this for Harvold type activator which constructed to open the bite beyond the freeway space
For twin block which require at least 5mm of vertical separation in the buccal segment to allow
for inclines occlusal plane
Medium opening activator:
One-piece functional appliance, with minimal acrylic to improve patient comfort
The lower acrylic extended lingually to the lower labial segment only, the upper and lower parts
are joined by two rigid acrylic posts leaving breathing holes anteriorly
There is no molar capping on the lower posterior teeth, these teeth are force to erupt
Tooth born – Myodynamic – class II
Andresen working hypothesis:
1- According to the original Andresen – Haupl concept, the force is generated in activator
therapy due to muscle contraction and myotatic reflex activity
= a successful treatment depends on muscle stimulation, frequency of movement of
mandible, and duration of effective force
= Ralf Grede 1952 suggested that such adaptation was possible only with small bite opening
up to 4mm
2- According to second work: the appliance is squeezed between the jaws in splinting action
= the appliance exerts forces that move the teeth in this rigid position
= an efficient stretch action is achieved by over-compensation and viscoelastic properties
of soft tissues
3- Third approach: called transitional type of activator action, which uses muscle contraction
and viscoelastic properties of soft tissue.
= this appliance in this group have a greater bite opening than recommended by Andresen
and Hauple, they do not over-compensate as do by Harvold
5-Oral screen
His: 1874
Newell: 1912
Oral screen: touch teeth
Vestibular screen: not contact any teeth
Modifications:
1- Hotz: with metal ring projecting between upper and lower

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2- : acrylic or wire at lingual side
3- Kraus: double oral screen, one lingual and the other labial
Vestibular screen:
= the basic appliance for screening therapy is the vestibular screen, the most common modification
is the lower lip shield, tongue crib, the combination of vestibular screen with breathing holes and
tongue crib
= unlike the construction bite for an activator, an edge to edge is taken, without consideration of
facial pattern
= the casts must reproduce the depth of vestibular sulcus and facial fold for proper fabrication of
the screen
= the vestibular shield extends into the vestibular sulcus to the point where the mucosal tissue
reflects outward. Care must be taken not to imping on muscle attachment, the Frenum, etc., it is
wise to desired extension of the screen in pencil on the models, this should approximate the
configuration of a full denture periphery.
Vertically the appliance extends from the upper and lower labial fold and distally as far as the
distal margin of last erupted molar. If the acrylic is overextended it will be uncomfortable to the
patient when attempting to close the lips, impinging on the mucosa. Lip seal with comfort is very
important.
However, if the screen is too short, it will be in-adequately anchored in the soft tissue and will tip
causing uncontrolled loading and movement of the upper incisors
= some clinicians believed that the vestibular screen is contraindicated in class II div 1
malocclusion with deep bite because of the tendency to tip the maxillary incisors lingually. If the
screen is fabricated in the proper forward construction bite, the mandible can move only anteriorly
from its retruded position. Lingual tipping of the teeth can be prevented if there is no contact
between the shield and incisors teeth
= to ensure that unwanted pressures are not created, the articulated models are covered with 2-
3mm of wax over the labial surface of the teeth, if one dental arch is crowded and the other is
relatively normal, the layer of wax on the crowded arch should be thicker
= the appliance should be worn at night 2-3 hours/day when the child is not in school
Uses of the appliance:
1- It is effective in eliminating abnormal sucking habits and lip dysfunction
2- It helps to establish a proper lip seal
3- It acts indirectly by influencing the posture of the tongue, the shield interrupts the contact
of the tip of the tongue and lower lip, a habit of the mandible of the infantile suckling pattern,
this leads to maturation of the deglutition cycle, with the creation of a somatic swallowing
pattern
= when there is mouth breathing habit with allergies present, some patients have difficulty sleeping
with the appliance. In these cases, breathing holes can be made in the anterior part of the screen
at the inter-incisal level
= as the patients wear the shield and shows progress holding the appliance well in the vestibule,
the acrylic periphery can be reduced, the lower margin can also be trimmed 2-3mm which will
enable a better lip seal to be achieved
6- Teuscher
Headgear + activator: Teuscher 1978
Benefit of activator and headgear but cannot worn full time, torqueing axillaries for upper incisors

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Dr. Mohammed Alruby
7- Frankel appliance
1980
= a series of removable appliance or functional regulators developed by Rolf Frankel in Germany
Known as: Frankel appliance, Or vestibular appliance, Or oral gymnastic appliance, it correct
and regulate the abnormal perioral muscles, it is myotonic
= it designed to change the muscular and soft tissue environment of the jaws and therefore modify
growth
= this achieve with use of wires and acrylic shield to displace the cheeks and lips away from the
teeth as well as encourage forward position of the mandible
= buccal shield remove pressure from the cheeks to allow for passive arch expansion
= lower labial acrylic pads are designed to gently imped the activity of mentalis muscle thought to
be an etiologic factor in the increased overjet seen in certain patient
= tissue born = class II
= treat: class II div 1
Class II di 2
Class III
Anterior open bite malocclusion
8- Herbest appliance
= it is fixed functional appliance, most popular in US, introduced by Emil Herbest in early 1900
and introduced at international dental congress at Berlin 1905
= this appliance was forgotten and has been popularized by Hans Puncherz at 1979
= protrusion of mandible is achieved via bilateral telescopic apparatus attached to maxillary 1st
molars and mandibular 1st
premolar bands. Each telescopic arms consists of: tube, plunger +
2screws and 2 pivot, which allows for opening and some lateral excursion with these arms
advancing the mandible so that the incisors are edge to edge
= reduction in overjet in 6 – 8 months ( Puncherz 1982)
Character:
1- tooth born
2- Class II, III
3- Fixed, cannot remove by patient
4- Full time wear
Types:
- Bonded
- Banded
Treatment effects:
1- Class I molar relation or over corrected
2- increase in mandibular growth
3- certain amount of distal driving of maxillary molars that helps in correction of molar
relationship
4- overjet reduction by increase in mandibular length and proclination of mandibular incisors
5- inhibit sagittal maxillary growth
6- increase SNB angle
7- decrease SNA angle
failure rate: 13% Herbest, 34% Twin block
Advantages:
1- not removed by patient, action produced is continuous
2- treatment duration is short due to continuous nature of action

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3- less patient cooperation is needed
4- can be used successfully in patient who are at the end of their growth
5- used in patient with mouth breather habit
disadvantage:
1- Minor functional disturbances in masticatory system which are temporary and gradually
disappear
2- Increased risk for development of dual bite
3- Repeated breakage and lessening of the appliance occurs especially in lower premolar area
4- Plaque accumulation and enamel decalcification occur especially in the splint type of
appliance
5- Tendency for posterior open bite at termination of therapy
9-Jasper Jumper
Relatively new type of appliance, flexible fixed, tooth born functional appliance
Introduced by J J Jasber 1980 similar to Herbest but lack of rigidity
Design:
= constructed of stainless steel coil and cap with cover of ploy-urethane for hygienic and comfort
= Jasber introduced in seven sizes ranging from 26mm to 38mm in length
= the end cap attached to maxillary posterior and mandibular anterior region
- Attached in upper arch by ball pin pass through the face bow tube of upper 1st
molar
- Attached in lower arch distal to mandibular canine by small bayonet and Lexan bead
= the length of force module is selected by adding 12mm to measured length
Indications:
In cases of mandibular defect and maxillary excess
Fabrication:
Measure length from tube of U6 to distal aspect of L3 and excess length about 12mm to give
required optimum force therapy producing mesial force in lower arch and distal force on maxillary
one
Effect of Jasber Jumber:
1- Skeletal effects: 40%
Displace maxilla distally
Shift A point distally
Clock wise rotation of mandible
Condyle moves forward
2- Dental effects: 60%
Posterior tipping and intrusion of molars
Backward tipping of upper incisors
Anterior tipping of mandibular teeth
Intrusion of mandibular incisors
Jasber stated that class II correction with appliance was about:
20% maxillary skeletal straining
20% backward dento-alveolar movement
20% forward dento-alveolar movement of mandible
20% condylar stimulation

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20% downward and forward remodeling of glenoid fossa
Advantages:
1- Produce continuous force
2- Do not require patient compliance by way of timely wear
3- Allow greater degree of mandibular freedom than Herbest appliance
4- Oral hygiene is easier to maintain
Appliance fitting and reviews:
= appliance should be fitted within two weeks of impression taken to insure good fit
= patient shown the appliance before fitting
= once fit the appliance, instruction for minimum time wear require / day
= use of calendar is good to improve compliance and wear
= patient should review one month following appliance fitting
= at each visit: Overjet and buccal segment relationship should be recorded
= if no changes of overjet or buccal segment is seen within six months of appliance being fitted the
treatment plane should be reviewed
N:B: clinical effect of functional appliances:
All functional appliances have similar effects which are dento-alveolar
1- Retroclination of maxillary incisors
2- Proclination of mandibular incisors
3- Mesial eruption of mandibular buccal dentition
4- Distal tipping of maxillary dentition
5- Restrain forward maxillary development
6- Forward movement of mandible due to small additional growth at condyle and remodeling
at glenoid fossa
10-Harvold appliance
The main modification from Andresen appliance for class II activator are as follow:
1- Extension of the lower acrylic over the incisal edges and on the labial surfaces of lower
incisors in an attempt to limit the tendency of the appliance to proclined the lower anterior
teeth
2- Maximum extension of the lower lingual flanges in order to redistribute as much of the class
II force as possible on to the muco-periosteum of the mandible
3- The design of the appliance in the buccal segments involves a totally different concept to
that of the Andresen. Occlusal shelves which are flat contact the cusp tips of upper buccal
segment teeth. This is in contrast with interdental facets of the Andresen which are designed
to guide the eruption of upper teeth distally and bucally at the same time as the lower teeth
are guided distally
4- By with other functional appliances, there is a considerable increase in the vertical
dimension of the appliance which is achieved by taking a working occlusal registration
extending well beyond the freeway space
This bite registration should give a separation of anterior teeth of the order of 1cm as
opposed to the 2 -3 mm associated with Andresen appliance
11- Bimler’s appliance (Gebissformer)
= Bimler in 1952 attempt to overcome the comparative rigidity of the activator by an appliance of
greater elasticity to encourage oral function during tooth movement. The appliance has a wire
skeleton with two acrylic palatal wings against the buccal teeth segments

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Dr. Mohammed Alruby
= while it is less bulky than activator, it is easier to deform during use and it is more complicated
to construct. The mandibular portion consists of a lingual arch, formed along the inside of
mandibular teeth on each side continuing in posterior loops with the ends fixed in the acrylic of
maxillary portion.
= the maxillary portion is provided with a labial arch, transverse sections along the inside of
maxillary incisors teeth and posterior coffin springs leaving the greater part of the roof of the
mouth uncovered. An acrylic layer is attached to the labial arch covering the mandibular incisor
teeth
= the elastic framework permits lateral excursion of the mandible to a limited degree. It is useful
in expanding the dental arches
= by using Bimler the treatment time is shortened because the appliance is wear all the day
Types of Bimler appliances:
1- Type A:
Has a performed labial splint on the labial aspect of the lower incisors and springs on the lingual
aspects of the lower incisors, the mandible held in its postured position by the incisors engaged
this splint.
There is a lower labial wire which holds the splint in position and connects distally with the acrylic,
thereby to the upper part of appliance. The upper part of appliance carries a labial arch and
palatal spring. The two acrylic springs are connected by coffin spring
2- Type B:
Has acrylic palatal coverage, with a midline screw and there is no labial arch on the upper incisors
3- Type C:
Has occlusal wires covered with plastic tubing to achieve bite opening. There is no labial splint,
but the lower incisors are retracted by a labial bow originating from the upper part of the
appliance.
12- Hamilton expansion Activator
It is a variant of the traditional monoblock, the first generation of such appliances was removable
and yet achieved stable correction, current bonded appliance reduces the need for patient
compliance and have a high level of success
Most patients with these functional appliances need second period of therapy
13- Double plates
= Martin Schwarz introduced the double plate because he recognized that the Monoblock was
bulky and difficult to wear
= upper and lower removable appliance were held in place with opposing occlusal guiding ramps
postured the mandible forward as the jaws were closed
= day time wear and patient compliance were significantly improved, the Schwarz plate was the
historical precursor of William Clark twin block appliance
14- Frankel Functional Regulator
= unlike conventional activator, the major part of Frankel appliance is confined to the oral
vestibule, the buccal shield and lip pads effectively hold the buccal and labial musculature away
from the teeth and investing tissues. Frankel believes that this active muscle and tissue mass (the
buccinator mechanism and orbicularis oris complex) has a potential restraining influence on the

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Dr. Mohammed Alruby
outward development of the dental arches, particularly during the transitional period of
development
= so when the buccinator mechanism pressures are screened from the dentition significant
expansion may be attained in the critical intercanine dimension, this relief crowding so often seen
in the lower anterior segment
= Frankel believes that the tongue plays a significant role in the ultimate outward progression of
the teeth and investing tissues. He also thinks, however that its effect has been overstressed to the
limit that equally important buccal musculature has been excluded
= an important part of Frankel philosophy is the fact the FR is anchored to the maxillary dental
arch via wires between the contacts at the mesial of the permanent maxillary 1st
molars and the
distal of the deciduous maxillary canines
The teeth must be separated to allow the wires to pass through the contacts, below the occlusal
surface. This may mean actual disking of the distal surface of the deciduous canine and second
molars. Simply allowing the wires to rest on these embrasures from the occlusal is totally
inadequate because:
1- They allow the same undesirable effect of lower incisor labial tipping as is seen with the
conventional activator
2- There is a potential damage to the labial gingival tissue by the lip pads as the appliance
moves up and down during the day.
= the labial wire of the Frankel appliance rests on the maxillary incisors, but it is not activated or
((Pinched up)) as often done with Hawley retainer to close spaces. This action tends to tip the
incisors excessively to the lingual and their spaces labially if the teeth rock on the lingual alveolar
plate.
= Frankel has stressed another theoretical action of the buccal shield and lip pads, in addition off
deforming muscle action and permitting the teeth to erupt downward and outward, he believes that
by extension of the shield and pads into the actual depth of the vestibule he can put the tissue under
tension without irritation. This tension exerts a pull in the congruous periosteal tissue of the
maxillary bone.
Types:
1- FR1 for correction of class I and class II div 1 malocclusion
2- FRII fro correction of class II div 2 and 1 cases
3- FRIII for correction of class III
4- FRIV for correction of open bite bimaxillary protrusion
1- FRI:
FRIa:
= there are actually three FRI appliance modification, however the original FRIa, with a lingual
wire loop instead of an acrylic lingual mandibular pad, is now seldom used
= perhaps the best use of the FRI has been in class I malocclusion cases. with minor crowding or
with delayed development of the basal bony and dental structures and deep bite cases with
protruded maxillary and retruded mandibular incisors
= although the appliance is occasionally used for class II div1 malocclusion in which the overjet
does not exceed 5mm, the lingual acrylic construction of the FRIb is generally preferred
Components:
1- Vestibular shields are a unique component of the Frankel appliance
2- The labial pads, or pelots (as Frankel calls them) are analogous to some of the lip bumper
3- Connecting wires between the shields and pads
4- Maxillary labial bow with canine loops

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Dr. Mohammed Alruby
5- Palatal bow shaped like coffin spring with the open end facing mesially the buccal extension
of the loop passes through the embrasure between the permanent 1st
molars and deciduous
molars and are anchored on each side in the buccal shield. It is imperative that these lateral
extensions insert below the occlusal surface of the embrasures to lock the appliance on the
maxillary arch and prevent a free float. The locking of the FR appliance on the maxillary
arch is accomplished largely by this firm insertion in the embrasure
6- Lingual bow with a U loop extending downward to the floor of the mouth to fit against the
lingual tissue below the incisors, the objective is to provide a signal to the mandible to
remain in the forward position when the mandible remains in the forward position when the
appliance is worn to correct a class II condition being held forward by protracting muscles
and not by the appliance itself
== function of different component parts of the appliance:
1- The palatal bow is needed to provide rigidity for the appliance since there is no palatal
acrylic
2- Buccal shield:
- Relieve pressure from the buccinator mechanism
- Create slight tension on the connective tissues fibers in the sulci to stimulate periosteal pull
with an intermittently outward force aided by lip seal exercises
3- The lip pads:
- Eliminate the abnormal perioral muscles activity, particularly of the hyperactive and
potentially deforming mentalis muscle
- Periosteal pull labially from the lip pads pressure in the anterior vestibular depth which
exert a bone- growth stimulate, reducing the pronounced mento-labial sulcus
- They form the labial boundary of the mandibular posturing trough
FRIb:
= the FRIb has largely replaced the FRIa with the exception of substituting a lingual acrylic pad
for the lower anterior wire loops to maintain forward mandibular posture, it is essentially the
same.
= Frankel suggested the use of this appliance in class II div 1 malocclusion with a deep bite and
an overjet that does not exceed 7mm
Construction bite:
= for minor sagittal problem 2-4mm the construction bite is taken in an end to end incisal
relationship as with the Bionator and care should be taken not to cause obvious strain of facial
muscles. The vertical opening should be only large enough to allow the crossover wires through
the inter-occlusal space without contacting the teeth.
= a tongue blade is sometimes placed between the teeth during taking of the construction bite to
establish sufficient vertical clearance for the crossover wires.
= if 6mm of sagittal movement is needed to correct the anterior posterior relationship, a
construction bite of 3mm forward posturing permits easy adaptation by the patients
FRIc:
=the FRIc is recommended by Frankel for more severe class II div1 malocclusion in patients with
an overjet of more than 7mm thus the mandibular protraction is done in two or occasionally three
steps
= the buccal shields are split horizontally and vertically into two parts; the anterior-inferior
portion contains the wires for the lingual acrylic pressure pad and for the lower lip pads

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Dr. Mohammed Alruby
= the vertical split is pried open with an office knife to the desired position by 2-3mm advancement
and then filled with cold-cure acrylic and polished
FRII:
= although the FRII has been used by Frankel mostly for class II div 2 malocclusion, it can be used
for class II div 1 patients
= the complaint encountered from some clinician is that the FRI canine loop can interfere with
eruption of the permanent canine and that the FRII canine loop is likely to do this
=Frankel also has used active plates to align the maxillary anterior teeth before placing the FRII
=construction:
The FRII is modified by adding a stst lingual bow 0.8mm behind the maxillary incisors, this serves
to maintain the pre-functional appliance alignment achieved and stabilize the appliance by helping
to lock it on the maxillary arch
= the maxillary lingual bow originates in the vestibular shield and passes to the lingual through
the canine –deciduous first molar embrasure, which has been previously notched, the wires forms
the loops that approximate the palatal mucosa and recurve vertically to contact the incisors at the
canine –lateral incisors embrasure
= the FRII canine loop are modified, they continue to originate in the buccal shields, but they
contact the canines on the buccal only as a recurved loop. They serve as an extension of the buccal
shields in the canine area, which is narrowed most by the abnormal perioral muscle function
associated with the malocclusion, placing these wires 2-3mm away from the deciduous canines
eliminate the restrictive muscle function, permitting the needed width development
FRIII:
It is used when there is a deficiency in the maxillary arch instead of the mandible
The lip pads are situated in the labial vestibular sulcus of the upper incisor segment, instead of the
lower, the purpose of the lip pads are:
1- Eliminate the restrictive pressure of the upper lip on the underdeveloped maxilla
2- Exert tension on the tissue and periosteal attachment in the depth of maxillary sulcus
stimulation of bone growth
3- Transmit upper lip force to the mandible via the lower labial arch for a retrusive stimulus,
but such force is quite minimal and probably has little effect other than to give a negative
feedback signal to false anterior posturing
The labial bow:
Rest against the mandibular teeth and not the maxillary incisors, which are free to move forward.
Unlike the maxillary bow, there is a positive contact with the lower incisors by the wire, the labial
bow should cross the lower incisors at the lowest possible level, without impinging on the
interproximal soft tissue, to keep lingual tipping of the lower incisors to a minimum
The palatal bow:
A small posteriorly directed loop at midline, approximates the palatal mucosa in the same manner
as is seen with the FRI and II. The difference is that the ends of the bow pass distal instead of
mesial to the permanent first molar, or the permanent second molar if it has erupted. The palatal
bow capable of delivering a slight anterior stimulus to the maxillary dentition by reforming the
wire to contact the distal surface of the terminal molars at the tuberosities
N: B: FRIII is not locked on the maxilla by the cross wires from the protrusion bow and palatal
bow, however the close difference of the buccal shields and lower labial wires to the mandibular
basal bone and lower incisors gives a firm grip on the mandibular dento-alveolar structures

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Dr. Mohammed Alruby
The buccal shields:
Stand away from the maxillary posterior dentoalveolar structures, similar to FRI and
approximately 3mm, but they are in contact with the mandibular teeth and mandibular apical base.
Any constricting or deforming effect of the buccinator mechanism and orbicularis oris is screened
from the maxillary arch and supporting bone
Construction bite:
It is done by clinically retruding the mandible as much as possible with the condyle occupying the
most posterior position in the fossa, the vertical dimension is opened only enough to allow the
maxillary incisors to move labially past the mandibular incisors from cross-bite correction. The
bite opening is kept to a minimum to allow lip closure with minimal strain
FRIV:
= aberrant muscle activity can create open bite problems and can redirect growth more vertically,
the FRIV reserve the unfavorable growth guidance, so it must be used during an active growth
period
= the FRIV has the same vestibular configuration as the FRI and FRII, but it has no canine loops
or protrusion bow, there are four occlusal rests on the maxillary 1st
permanent molars and
deciduous molars to prevent tipping of the appliance. The rests discourage any eruption of
posterior teeth, which is important in anterior open bite conditions. The palatal bow is like that of
FRI and is always placed behind the last molar, the occlusal rests often must be adapted to the
individual patient. They must now prevent shifting of the appliance in a posterior direction, hence
the appliance is not locked on either arch interproximal wires, occasionally a thin difficult
Mode of action of function regulator:
= the Frankel appliance uses the vestibule as its area of operation and with holds muscle pressure
from the developing jaw and dento alveolar area. Instead of using jackscrews, Coffin spring, finger
spring or selective grinding of acrylic, as is done with activator, it achieves its effect through the
relief of forces exerted by the surrounding neuromuscular envelope.
= the appliance is entirely tissue born on the lower arch, since the spring wires behind the
mandibular incisors are completely passive and may actually stand 0.5 – 1mm from the cingula,
except when a mild depressing force is desired
= the appliance is capable of achieving the following changes to the orofacial complex:
1- Enlargement of both sagittal and transverse intra-oral space
2- Increase of vertical intra-oral space
3- Forward posturing of mandible
4- Improvement of muscle tonus and establishment or proper oral seal. With the development
of proper oral seal, with the development of new neuromuscular pattern
15- Lower lip shield
= The lower lip shield is really just the lower half of a full vestibular shield, it is extended into the
vestibular sulcus to the depth of the labial fold and as far as the distal margin of the last molar
= Although the appliance is made on lower cast only, the occlusal relationship should be
considered, it extends superiorly to the incisal third of the lower teeth however, if this disturbs the
occlusion, the margin must be reduced
= Anchorage can be improved after eruption of the permanent first molar by adding reverse Adams
type clasps to these teeth (wire framework on the lingual, the clasps anchored in buccal acrylic)
the lower lip shield has the added advantage of being wearable during the day, both at school and
at the home. Talking can be quite normal after some practice.

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Dr. Mohammed Alruby
= The purpose of the lower shield is to eliminate the persistence and pernicious hyperactivity of
the mentalis muscle, with its forcing of the lower lip into the overjet space
= As soon as the overjet diminishes and normal lip seal is established, which can happen quickly,
even potentially incompetent lips, use of the shield is discontinued, but if a residual hyperactivity
of the mentalis muscles remains, the shield should be worn until this extra-oral manifestation of
abnormal function is eliminated. A spontaneous uprighting of the lower incisors in any of these
cases, with resultant de-crowding
16- Tongue Crib
= if the patient thrust the tongue interdentally in either the anterior or posterior regions of the
dental arches, a malocclusion can result, however a tongue crib with removable or fixed appliance
can inhibit this abnormal function
= with a removable appliance the crib for an anterior open bite consists of a palatal plate with
horse shoe- shaped wire crib, the plate ca
N be anchored with arrowhead or Adams clasps. The crib length (6-12mm) and its distance from
the lingual surface of upper incisors (3-4mm) the crib is placed in the area of the local tongue
dysfunction and resultant malocclusion.
= it should neither touch the teeth nor disturb the occlusion, it can be made out of 0.8mm wire or
formed of acrylic. It acts as inhibitory appliance only, so the acrylic construction should not
interfere with the improvement of open bite
= the tongue crib is not exclusively a screening device; some elements of the appliance can
incorporate in its design:
1- The labial bow not only helps retention but also can tip the upper incisors lingually
2- If the crib is placed at gingival third, a proper adjustment can stimulate the eruption of these
teeth, a movement needed in open bite problems
3- The acrylic can also be interposed between the teeth covering the occlusal surfaces of upper
molars to prevent eruption of these teeth while enhancing anchorage of the palate. This
especially beneficial in open bite problems, the bite blocking here can be 3 – 4mm which is
usually beyond the postural vertical dimension in open bite patients
4- The appliance can also incorporate expansion screw, since many open bite problems also
have a narrow upper arch
Posterior tongue crib:
Appliance such as a posterior tongue crib are used in case of unilateral or bilateral open bite and
true deep over bite (with infra-occlusion of molar segment) the posterior appliance consists of a
plate attached to the teeth with clasps and supported by a labial bow.
18- combination of vestibular screen and tongue crib
A crib of wire or acrylic can be placed in the area of the open bite and attached to the
vestibular screen by wire that extended around the last molar tooth or it may be passed through
the inter-occlusal space in the region of the canine and first premolar. In either instance it should
not touch the teeth, even in occlusion

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Dr. Mohammed Alruby
19- Positioner
These devices are usually used as retaining appliances following fixed appliance treatment,
are made of flexible plastic and carry impressions of upper and lower dental arches, they are made
into a slightly over-treated class I relationship. The patient wears the positioner immediately
following band removal and is taught to clench the teeth into the positioner. The action is
combination of molding the individual teeth into their correct positions within the arches by the
effect of the plastic in contact with the teeth, but it also has a functional element of establishing a
correct inter-arch relationship.
20- Lip Bumper
= This appliance which can be used in both the maxilla and mandible uses the muscular force from
the upper or lower lip to provide a distal force, usually to the 1st
molars, the appliance has
something in common with the labial pads on the FR appliance which also displace the lip forward
and perhaps downward
= In lower arch, the appliance has two effects:
1- Firstly, by removing the soft tissue forces from the labial aspect of the lower anterior it may
produce forward tilting of these teeth under the influence of the tongue. This movement may
be undesirable but can be reduced by siting the bumper as low as possible in the labial
sulcus so that the upper part of the lip able to maintain contact with the incisors this
unwanted effect can also be controlled of the lower anterior teeth are banded
2- Move the anchor teeth distally (usually 1st
molar) the degree of distal movement can be very
limited, especially where the second molars are erupted such distal movement is most
effective when lower second molars have been extracted, usually in an arch where only a
small amount of distal movement of the first molars is required to relief anterior crowding